物理化学学报 >> 2013, Vol. 29 >> Issue (04): 837-842.doi: 10.3866/PKU.WHXB201301241

催化和表面科学 上一篇    下一篇

NO2在Ag/Pt(110)双金属表面上的吸附和分解

李金兵1, 姜志全2, 黄伟新2   

  1. 1 中国石化北京北化院燕山分院, 北京 102500;
    2 中国科学技术大学合肥微尺度物质科学国家实验室(筹), 中国科学院能量转换材料重点实验室和化学物理系, 合肥 230026
  • 收稿日期:2012-11-28 修回日期:2013-01-21 发布日期:2013-03-25
  • 通讯作者: 姜志全, 黄伟新 E-mail:jzhiquan@ustc.edu.cn; huangwx@ustc.edu.cn
  • 基金资助:

    国家自然科学基金(11079033)资助项目

Adsorption and Decomposition of NO2 on Ag/Pt(110) Bimetallic Surface

LI Jin-Bing1, JIANG Zhi-Quan2, HUANG Wei-Xin2   

  1. 1 Yanshan Branch of SINOPEC Beijing Research Institute of Chemical Industry, SINOPEC, Beijing 102500, China;
    2 Hefei National Laboratory for Physical Sciences at the Microscale, Chinese Academy of Sciences, Key Laboratory of Materials for Energy Conversion and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, Anhui, China
  • Received:2012-11-28 Revised:2013-01-21 Published:2013-03-25
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (11079033).

摘要:

利用俄歇电子能谱(AES)和程序升温脱附谱(TDS)研究了NO2在Ag/Pt(110)双金属表面的吸附和分解.室温下NO2 在Ag/Pt(110)双金属表面发生解离吸附, 生成NO(ads)和O(ads)表面吸附物种. 在升温过程中NO(ads)物种发生脱附或者进一步分解. 500 K时NO2在Ag/Pt(110)双金属表面发生解离吸附生成O(ads)表面吸附物种. Pt 向Ag传递电子, 从而削弱Pt-O键的强度, 降低O(ads)从Pt 表面的并合脱附温度. 发现能够形成具有稳定组成的Ag/Pt(110)合金结构, 其表现出与Pt(110)-(1×2)相似的解离吸附NO2能力, 但与O(ads)的结合明显弱于Pt(110)-(1×2). 该AgPt(110)合金结构是可能的低温催化直接分解氮氧化物活性结构.

关键词: Ag/Pt(110)双金属表面, 二氧化氮, 化学吸附, 分解, 助剂作用

Abstract:

The adsorption and decomposition of NO2 on Ag/Pt(110) bimetallic surfaces have been investigated by Auger electron spectroscopy (AES) and thermal desorption spectroscopy (TDS). At room temperature, NO2 undergoes dissociative chemisorption on Ag/Pt(110) bimetallic surfaces, forming chemisorbed NO(ads) and O(ads). Upon heating, NO(ads) undergoes both desorption from the surface and further decomposition. At 500 K, NO2 chemisorbs dissociatively on Ag/Pt(110) bimetallic surfaces, forming O(ads). Electron transfer occurs from Pt to Ag, therefore, the presence of Ag on Pt(110) surface weakens the binding energy of O(ads) with the surface and decreases the temperature required for the recombinative desorption of O(ads) from the surface. We observed the formation of a Ag/Pt(110) alloy structure that exhibits catalytic activity towards NO2 decomposition similar to that of Pt(110)-(1×2) but with a binding energy towards O(ads) much lower than that of Pt(110)-(1×2). Such a Ag/Pt(110) alloy structure may be active in catalyzing the direct decomposition of NOx at relatively low temperatures.

Key words: Ag/Pt(110) bimetallic surface, NO2, Chemisorption, Decomposition, Promotion effect

MSC2000: 

  • O643